The objectives of this project are to develop a rapid and specific immunochemical method for identification of human periodontal plaque bacteria. Identification will be by means of highly specific and possibly monospecific antisera developed and analyzed by means of two-dimensional electroimmunodiffusion (2-D EID). Specific immunochemical identification will be confirmed with the electron microscope in both pure cultures and directly in plaque. Correlations will be made between identifiable microorganisms present in a spectrum of periodontal diseases and in health.